Automatic compensating freezing and heating recipes

ABSTRACT

A method of adjusting a base recipe for a product introduced into a processor, includes providing a base recipe used by the processor on the product, identifying at least one parameter of the base recipe to be altered to compensate for at least one corresponding physical parameter of the product discharged from the processor, automatically changing the base recipe in response to the at least one altered parameter to compensate for the at least one physical parameter of the product discharged, and processing new product introduced into the processor with the changed base recipe.

The present embodiments relate to control of recipes for processingproducts, such as for cryogenic freezing and chilling of food andpharmaceutical products.

The ability to select a recipe for a freezing or chilling process isbecoming common in new freezing and chilling systems. A recipe is aseries of predetermined parameters, which establishes the adjustment ofprocess equipment system variables to a particular product beingprocessed to achieve the desired output quality for the product.

Use of a recipe may be applied to any process, such as for example foodfreezing. To achieve a production rate of 6000 pounds per hour (lb/hr)of hamburger patties for example, with a fixed product inlet temperatureand a desired outlet temperature, a recipe can be created so that afreezer will operate at a fixed freezing temperature, conveyor beltspeed (residence time) for the product, and fan speed to match therequirements. The operator simply selects a recipe from a menu and thefreezer adjusts to the above pre-defined parameters of the recipe.

The problem with known systems is that they do not account forday-to-day or even hour-to-hour deviations in product parameters beingprovided to the process, such as for example variability in productionrates and product inlet temperatures. In addition, freezer performancecan deteriorate over time, thereby adversely impacting a temperature ofthe product from the instance it enters the freezer. To compensate forthese conditions, an existing recipe must be manually superceded tochange process equipment parameters to accommodate the changed qualitiesof the product being processed. This defeats the intended purpose of therecipe, since the operator must then guess or estimate as to whichparameter(s) to change and to what degree in order to accommodate thechanging variables of the product to be processed. For example, does theoperator increase or decrease the amount of freezing medium, theresidence time of the product in the freezer, the heat transfercoefficient (fan speed), and if so, in which combination? A humanoperator would not be able to make this determination accurately inorder to provide the most cost-effective way to proceed to bring theproduct “on-spec” at discharge.

DESCRIPTION OF THE INVENTION

The enhancement embodiments to a recipe driven control system are tohave the ability for the process equipment controls to “alter” a recipethrough operator input of the changed product parameter and by means ofinternal process calculation, optimise the process either by theoperator's desired affect or by optimising process efficiency. Forexample, if a plant operator were to input new product infeedtemperature, then the freezer controls will determine how to bestcompensate process parameters and make the necessary change in eitherprocess temperature, fan speed, product residence time, or possibly acombination of these elements.

The inventive embodiment compensates for “off-spec” product, i.e. theprocessing system will change or alter machine control parameters tobring subsequent product back into “spec”. Machine recipe settings caninclude multiple parameters, and changing any one of said parameterswill affect to some degree the result of the process. The presentembodiments eliminate operator guesswork when changing machineryparameters, such as freezer or oven parameters, through programming notpresently available. This is accomplished by establishing a hierarchy ofparameters so that a proper parameter is changed along with an internalcalculation to establish the degree to which the parameter will bechanged. The input to this control of the parameter will be throughoperator input (most likely but not necessarily temperature input) orthrough direct feedback from a sensor (such as for example a temperaturesensing device) generating a signal responsive to a processed product'stemperature.

There is provided a method of adjusting a base recipe for a productintroduced into a processor, which includes providing a base recipe usedby the processor on the product, identifying at least one parameter ofthe base recipe to be altered to compensate for at least onecorresponding physical parameter of the product discharged from theprocessor, automatically changing the base recipe in response to the atleast one altered parameter to compensate for the at least one physicalparameter of the product discharged, and processing new productintroduced into the processor with the changed base recipe.

The operator of the present embodiment selects a recipe, startsproduction with the recipe selected and monitors the product during andafter production to determine if the desired result is achieved. If theproduct result is not achieved, the product attribute which is“off-spec”, typically the product temperature, is input into theprocessor to adjust the recipe parameters to provide the desired productto be produced during the processing. Since the recipe parameters arechanged and displayed during processing, if the operator finds avariable or parameter which is undesirable, and the condition repeatsitself, the operator may chose to edit and restore a revised recipe.This will eliminate operator guesswork going forward due to storage ofthe new recipe for a particular product to be processed.

In general, the plant operator will measure and input the deviationnecessary to the known base recipes programmed into the freezer'scontrol system. The operator may adjust any or all of the variablesknown, such as for example inlet temperature of the product, residencetime of the product within the freezer, outlet temperature of theproduct, product surface area, product weight, product heat load,overall heat transfer co-efficient (fan speed) and moisture content,such that a required operating temperature of the freezer can becalculated and adjusted by the processor. Alternatively, through ahierarchy of parameters, if the product is being discharged or exhaustedat an undesirable temperature, the “out-feed” product temperature isinput into the processor for adjusting the freezer to a proper freezingparameter. That is, the operator would randomly sample product at theoutlet of the processor, such as a freezer or oven, to determine if thetemperature at the outlet is “on-spec” for subsequent use or furtherprocessing. For example, the out-feed product temperature may be desiredto be −20° C., when in fact the random sampling shows that the producttemperature is actually −5° C. Therefore, the operator would input intothe processor the product temperature at the outlet of −5° C. and theprocessor would scroll through the hierarchy of parameters to determinewhich parameter or parameters of the recipe should be altered for themost efficient and cost effective way to provide the product with atemperature of −20° C. at the outlet or discharge end of the processor.The processor will determine which of the parameters of cooling, heattransfer coefficient (fan speed) or residence time (conveyor speed) mustbe adjusted in order to provide the desired product temperature at theoutlet, while maintaining a high operating efficiency of the freezingprocess. The processor may determine to adjust one or more of theseparameters in the recipe so that the product being discharged is at thedesired temperature.

The embodiments of the present invention enable an operator of a foodprocessing plant, for example for freezing or chilling of food products,to select from among a plurality of known base recipes to be used withthe food product. For example, the plant operator will select the typeof product to be frozen, such as for example meat, poultry, fish,vegetables, fruit, bakery products, dairy products, processed foods,pharmaceutical products; and the freezer will prescribe the recipe to beused for such product. However, since the recipe as loaded into thefreezer is already pre-set, such a setting may only cause the freezer tofunction for the product selected at a specific input temperature,throughput volume (e.g. 300 units per hour), output temperature,moisture content, etc. That is, the operator is limited initially toselecting a recipe which, although such can be used for any type of foodproduct, such as chicken for example, such recipe may not be specificenough for the particular type of chicken product (or meat or fishproduct, etc.) that is actually to be chilled or frozen by the freezer.

In addition, product being introduced into the freezer may arrive froman environment that has drastically altered the product's temperatureand consistency from a recipe which is already stored in the processorfor the particular product. It would be extremely difficult if notimpossible for the operator to determine which parameters of the recipemust be altered, and by how much, in order to have the productintroduced at the inlet processed to a desired outlet temperature.Hence, a random sampling of the product at the outlet and input of suchdata into the processor insures that product being introduced into theinlet will be exposed to the necessary recipe to provide the productwith the desired outlet temperature.

Therefore, after the operator selects the base recipe, the operator thenmay adjust the recipe depending upon the particulars of the product atthe inlet, for example, to be frozen or chilled. So, for example, theoperator will know that the base recipe for chicken cutlets may be for acertain number of cutlets at a certain inlet temperature to be frozensuch that a certain output temperature is provided to the frozen orchilled cutlets. After the operator selects the initial base recipe, theoperator then adjusts the freezer control to the required inlettemperature setting by a switch on the control panel to be the knowntemperature of the food product being introduced into the freezer.Chicken products, for example, may be introduced to the freezer atdifferent temperatures and therefore, such temperatures may not be thesame as used in the base recipe. The necessity to change freezer controlparameters may also result from deviations in freezer performance, suchas for example ice build-up affecting convection circulation in thefreezer or environmental conditions, such as for example an unusuallyhot environmental at an exterior of the freezer (or an unusually coldenvironment at an exterior of an oven).

Similarly, the plant operator may elect to move 6,000 units per hourthrough the freezer, as opposed to the base recipe which takes intoaccount only 4,000 units per hour. Further, the operator may need theoutput temperature at 40° F., as opposed to say 50° F. which may bepre-set into the existing base recipe. Therefore, the operator willfurther select an adjustment to the freezer control for the throughputvolume of product and the desired output temperature of same. When allthese adjustments to input/output temperature, and throughput amount orquantity have been made, the freezer recomputes the amount of cryogen,mechanical refrigerant, speed of conveyance, etc., necessary for thisparticular product, including the residence time (or throughput time) ofthe food product to transit the freezer, such that the food product ischilled or frozen in the most efficient amount of time using only thenecessary amount of cryogen in order to effect the chilling necessaryfor the product to be on-spec at the outlet of the freezer.

Food products may have different moisture content. That is, certainmanufacturers of chicken for example inject marinate or otherpreservatives into the chicken product and this impacts temperature ofthe product to be introduced into the freezer, as well as product dwelltime in the freezer. The marinate may consist of a brine solution whichcould affect the temperature of the food product such that adjustmenthas to be made to the freezer control to accommodate an amount ofcryogen necessary to overcome the warming effect of the marinate orother brine product injected into the chicken patty. This condition maynot be immediately apparent until the product is inspected upondischarge from the freezer (or oven if used instead), in which case themeasured out-feed temperature of the product can be input into thecontrol system for same to adjust the cooling parameters to offset theunacceptable warming of the product.

Sensors may also be used to interface directly with the freezer control,or oven control, which sensors transmit a signal to the control of theparticulars of the food product to be frozen (or heated) such that thenecessary calculation can be made by the freezer control to the baserecipe, depending upon the particulars of the product to be frozen (orheated). That is, sensors may be disposed at an inlet and an outlet ofthe freezer (or heater) to sense the temperature of the productintroduced into and exhausted from the processor, instead of manuallysensing the temperature of the product at the inlet and outlet. Theactual temperature sensed of the product at the outlet is conveyed as asignal (wirelessly or otherwise) back to the processor control which inturn scrolls through the hierarchy of parameters to adjust theparameters of the receipt as necessary so that the product has thedesired temperature when it is removed from the outlet.

The embodiments discussed above are also applicable where the processoris an oven. In that regard, instead of a cooling substance, heat for therecipe can be provided to the processor by at least one of convectioncurrents, conduction and radiation.

It will be understood that the embodiments described herein are merelyexemplary, and that one skilled in the art may make variations andmodifications without departing from the spirit and scope of theinvention. All such variations and modifications are intended to beincluded within the scope of the invention as described and claimedherein. Further, all embodiments disclosed are not necessarily in thealternative, as various embodiments of the invention may be combined toprovide the desired result.

1. A method of adjusting a base recipe for a product introduced into aprocessor, comprising providing a base recipe used by the processor onthe product, identifying at least one parameter of the base recipe to bealtered to compensate for at least one corresponding physical parameterof the product discharged from the processor, automatically changing thebase recipe in response to the at least one altered parameter tocompensate for the at least one physical parameter of the productdischarged, and processing new product introduced into the processorwith the changed base recipe.
 2. The method of claim 1, wherein theprocessor comprises a freezer.
 3. The method of claim 1, wherein theprocessor comprises an oven.
 4. The method of claim 1, wherein the atleast one parameter comprises a parameter selected from at least one ofresidence time of the product in the processor, product inlettemperature, process temperature, product outlet temperature, productsurface area, product weight, product heat load, product heat transferco-efficient, fan speed, and product moisture content.
 5. The method ofclaim 4, wherein the at least one physical parameter of the productdischarged from the processor comprises a parameter selected from atleast one of product outlet temperature, product surface area andproduct moisture content.
 6. The method of claim 1, wherein the baserecipe comprises providing a chilling substance to the processor forcontacting the product.
 7. The method of claim 6, wherein the chillingsubstance comprises a cryogenic substance.
 8. The method of claim 7,wherein the cryogenic substance comprises nitrogen.
 9. The method ofclaim 6, wherein the chilling substance comprises carbon dioxide. 10.The method of claim 1, wherein the base recipe comprises providing heatto the processor for contacting the product.
 11. The method of claim 10,wherein the heat is provided to the processor by at least one ofconvection currents, conduction and radiation.
 12. The method of claim3, wherein the base recipe comprises introducing heat to the processorfor contacting the product.
 13. The method of claim 1, wherein theproduct comprises a food product.
 14. The method of claim 13, whereinthe food product is selected from meat, poultry, fish, vegetables,fruit, bakery products, dairy products and processed foods.
 15. Themethod of claim 1, wherein the product comprises a pharmaceuticalproduct.